Electromagnetic interference filter for implanted electronics

Abstract

An electromagnetic interference filter for various electronic devices such as implantable medical devices is provided. A plurality of signal electrodes can be configured in an array, where each signal electrode extends vertically from a top surface to a bottom surface of the filter such that the signal electrodes are flush with the top and bottom surface. Ground or common electrodes can have a parallel arrangement and be interposed between the signal electrodes. The ground electrodes can be grounded internally, externally, or both internally and externally. Dielectric material can be disposed between signal electrodes and ground electrodes to act as an insulator between adjacent electrodes.

What is claimed is: 
     
       1. An electromagnetic interference (EMI) filter, comprising:
 a plurality of signal electrodes arranged in a respective plurality of arrays, with each signal electrode extending vertically between respective top and bottom surfaces of the filter such that the plurality of signal electrodes are flush with the top and bottom surfaces, and wherein the EMI filter is configured to be coupled on said top surface of the filter to internal conductors of an implantable medical device and configured to be coupled on said bottom surface of the filter to external lead wires implanted within a body in which the medical device is implanted; 
 a plurality of ground electrodes arranged in parallel to each other and interposed between the plurality of signal electrodes, the plurality of ground electrodes grounded at least one of internally by being exposed on the top and bottom surfaces of the filter or externally by being exposed on a side surface of the filter; 
 dielectric material disposed between the plurality of signal electrodes and the plurality of ground electrodes to act as insulator material between adjacent signal and ground electrodes, and to define a filter body having a length along a longitudinal axis thereof, a thickness between the top and bottom surfaces thereof, and a width in an axis perpendicular to the longitudinal axis and the thickness; and 
 at least one metallization region applied to selected regions on the top and bottom surfaces of the filter to connect respective arrays of signal electrodes and provide an interconnection surface for electrically attaching the filter to other components; 
 wherein the filter acts as a shielding element to prevent unwanted electromagnetic interference with an input and output of the medical device. 
 
     
     
       2. An electromagnetic interference filter as in  claim 1 , further including:
 a passivation layer on at least one of the top and the bottom surface of the electromagnetic interference filter to prevent arcing between the plurality of signal electrode arrays. 
 
     
     
       3. An electromagnetic interference filter as in  claim 2 , wherein the at least one metallization region is further applied to selected regions on the side surface of the filter to connect selected pluralities of the ground electrodes and provide a further interconnection surface for electrically attaching the filter to the other components, with a portion of the interconnection surface exposed through the passivation layer. 
     
     
       4. An electromagnetic interference filter as in  claim 3 , wherein the at least one metallization region comprises termination surfaces coupled to the plurality of signal electrode arrays. 
     
     
       5. An electromagnetic interference filter as in  claim 4 , wherein the termination surfaces comprise one of a plate and connector couplers. 
     
     
       6. An electromagnetic interference filter as in  claim 3 , wherein the at least one metallization region comprises termination surfaces coupled with the plurality of ground electrodes. 
     
     
       7. An electromagnetic interference filter as in  claim 6 , wherein the termination surfaces comprise one of thin-film metallization and thick-film metallization. 
     
     
       8. An electromagnetic interference filter as in  claim 2 , further including:
 a solder ball connection which passes through the passivation layer. 
 
     
     
       9. An electromagnetic interference filter as in  claim 1 , wherein the at least one metallization region further includes ground terminations applied to selected regions on at least one of the top, bottom and side surface of the EMI filter so as to connect the pluralities of ground electrodes and provide a further interconnection surface for electrically attaching a ground to the filter. 
     
     
       10. An electromagnetic interference filter as in  claim 9 , wherein the plurality of ground electrodes are arranged in a vertical configuration, so that the plurality of ground electrodes are grounded internally. 
     
     
       11. An electromagnetic interference filter as in  claim 10 , wherein each ground electrode is arranged in the vertical configuration and flush with the top surface and the bottom surface of the filter, and with at least one end thereof flush with at least a side surface of the filter, so that the filter is also grounded externally. 
     
     
       12. An electromagnetic interference filter as in  claim 1 , wherein the plurality of signal electrodes have a preselected configuration and arrangement relative to the plurality of ground electrodes so as provide selected conductivity of an electrical signal applied to the plurality of signal electrodes or the plurality of ground electrodes, and to form a selected capacitance between adjacent signal and ground electrodes, for shunting unwanted high frequency interference away from the plurality of signal electrodes. 
     
     
       13. An electromagnetic interference filter as in  claim 1 , wherein the plurality of ground electrodes are grounded externally by being exposed and connected at a location on the side surface of the filter. 
     
     
       14. An electromagnetic interference filter as in  claim 1 , wherein the plurality of ground electrodes are grounded both internally and externally. 
     
     
       15. An electromagnetic interference filter as in  claim 1 , wherein each of said signal electrodes have a length dimension along the longitudinal axis of the filter which is less than one-half of the length of the filter along the longitudinal axis thereof. 
     
     
       16. An electromagnetic interference filter as in  claim 1 , wherein the at least one metallization region is further applied to selected regions on the side surface of the filter to connect to the pluralities of ground electrodes and provide a further surface for electrically attaching the filter to the other components. 
     
     
       17. An electromagnetic interference filter as in  claim 1 , wherein:
 each ground electrode is arranged in a vertical configuration such that each ground electrode is flush with the top surface and the bottom surface of the filter, and wherein each ground electrode further includes protrusions that are exposed on at least one of the top and bottom surfaces in regions distinct from the plurality of signal electrodes; and 
 the at least one metallization region of the filter further includes a termination surface coupled to the ground electrode protrusions so that the plurality of ground electrodes are grounded internally. 
 
     
     
       18. An electromagnetic interference filter as in  claim 17 , wherein one end of the plurality of ground electrodes is flush with the side surface of the filter, and the at least one metallization region of the filter further includes another termination surface which is coupled to the plurality of ground electrodes at the side surface so that the plurality of ground electrodes are also grounded externally. 
     
     
       19. An electromagnetic interference filter as in  claim 1 , wherein the filter is substantially monolithic. 
     
     
       20. An electromagnetic interference filter as in  claim 1 , wherein:
 each array includes at least two of the plurality of the signal electrodes arranged in parallel to each other in a relatively densely packed configuration such that current conductivity capability is between the filter top surface and the filter bottom surface. 
 
     
     
       21. An electromagnetic interference filter as in  claim 1 , wherein:
 the interconnection surface includes connection made thereto including at least one of a wire bonding, a ball-grid array coupling, a solder connection, and a castellation coupling. 
 
     
     
       22. An electromagnetic interference filter as in  claim 1 , wherein said plurality of arrays of signal electrodes each have a surface area less than the width of the filter and having an alternating arrangement. 
     
     
       23. An electromagnetic interference (EMI) filter, comprising:
 a plurality of signal electrodes arranged in a respective plurality of arrays, with each signal electrode extending vertically between respective top and bottom surfaces of the filter such that the plurality of signal electrodes are flush with the top and bottom surfaces; 
 a plurality of ground electrodes arranged in parallel to each other and interposed between the plurality of signal electrodes, the plurality of ground electrodes grounded at least one of internally by being exposed on the top and bottom surfaces of the filter or externally by being exposed on a side surface of the filter; 
 dielectric material disposed between the plurality of signal electrodes and plurality of ground electrodes to act as insulator material between adjacent signal and ground electrodes, and to define a filter body having a length along a longitudinal axis thereof, a thickness between the top and bottom surfaces thereof, and a width in the axis perpendicular to the longitudinal axis and the thickness; 
 a passivation layer on at least one of a top and bottom surface of the EMI filter to prevent arcing between the plurality of signal electrode arrays; 
 signal terminations applied to selected regions on the top and bottom surfaces of the EMI filter so as to connect the pluralities of signal electrodes and provide an interconnection surface for electrically attaching a signal with the filter; and 
 ground terminations applied to selected regions on at least one of the top, bottom or side surfaces of the EMI filter so as to connect the pluralities of ground electrodes and provide an interconnection surface for electrically attaching ground to the filter; and 
 wherein each of said plurality of signal electrodes have a length dimension along the longitudinal axis of the filter which is less than one-half of the length of the filter along the longitudinal axis thereof, and each of said plurality of ground electrodes have a length dimension along the longitudinal axis of the filter which is more than one-half of the length of the filter along the longitudinal axis thereof. 
 
     
     
       24. An electromagnetic interference (EMI) filter as in  claim 23 , wherein one end of the plurality of ground electrodes is flush with the side surface of the filter, and another termination surface is coupled to the plurality of ground electrodes at the side surface so that the plurality of ground electrodes are also grounded externally. 
     
     
       25. An electromagnetic interference (EMI) filter as in  claim 23 , wherein the plurality of signal electrodes have a preselected configuration and arrangement relative to the plurality of ground electrodes so as to provide selected conductivity of an electrical signal applied to the plurality of signal electrodes or plurality of ground electrodes, and to form a selected capacitance between the plurality of signal electrodes and the plurality of ground electrodes, for shunting unwanted high frequency interference away from the plurality of signal electrodes. 
     
     
       26. An electromagnetic interference (EMI) filter as in  claim 23 , wherein:
 each ground electrode is arranged in a vertical configuration such that each ground electrode is flush with the top surface and the bottom surface of the filter, and wherein each ground electrode further includes protrusions that are exposed on at least one of the top and bottom surfaces in regions distinct from the plurality of signal electrodes; and 
 the ground terminations are located on at least the top surface and bottom surface so that the plurality of ground electrodes are grounded internally. 
 
     
     
       27. Methodology for use of an electromagnetic interference (EMI) filter with an implantable medical device, comprising the steps of:
 providing a plurality of signal electrodes for an EMI filter, arranged in a respective plurality of arrays, with each signal electrode extending vertically between respective top and bottom surfaces of the filter such that the plurality of signal electrodes are flush with the top and bottom surfaces, and configured to be coupled on the top surface of the filter to internal conductors of an implantable medical device and coupled on the bottom surface of the filter to external lead wires implanted within a body in which the medical device is implanted; 
 providing a plurality of ground electrodes arranged in parallel to each other and interposed between the plurality of signal electrodes, and extending through the filter between the top and bottom surfaces thereof, for grounding connections on the surfaces; 
 applying metallization to selected regions on the top and bottom surfaces of the filter to connect respective arrays of the plurality of signal electrodes and provide an interconnection surface for electrically attaching the filter to other components; and 
 disposing dielectric material between the plurality of signal electrodes and the plurality of ground electrodes to act as insulator material between adjacent signal and ground electrodes, and so as to collectively form with the plurality of signal electrodes, the plurality of ground electrodes, and dielectric material a filter which acts as a shielding element to prevent unwanted electromagnetic interference with an input and an output of the medical device. 
 
     
     
       28. Methodology as in  claim 27 , further including:
 using the interconnection surface to electrically connect selected pluralities of electrodes of the filter to other components, wherein the connections are made using at least one of wire bonding, ball-grid array coupling, soldering, and castellation coupling; 
 and wherein providing the plurality of signal electrodes includes providing each of said plurality of signal electrodes with a length dimension along the longitudinal axis of the filter which is less than one-half of the length of the filter along the longitudinal axis thereof, and 
 wherein providing the ground electrodes includes providing each of said plurality of ground electrodes with a length dimension along the longitudinal axis of the filter which is more than one-half of the length of the filter along the longitudinal axis thereof. 
 
     
     
       29. Methodology as in  claim 27 , further including:
 forming a passivation layer on at least one of the top or the bottom surface of the electromagnetic interference filter to prevent arcing between the plurality of signal electrode arrays; and 
 grounding the plurality of ground electrodes internally by exposing the ground electrodes on the top and bottom surfaces of the filter or externally by exposing the ground electrodes on a side surface of the filter. 
 
     
     
       30. An electromagnetic interference (EMI) filter system for use with an implantable medical device, comprising:
 a canister with a bushing for enclosing at least one end of the canister; 
 a plurality of external connection wires passing through the bushing and coupling with an upper termination area of an EMI filter, and for connection with external circuitry of the implantable medical device; and 
 a plurality of internal connection wires coupling with a bottom termination area of said EMI filter, and for connection with internal circuitry of the implantable medical device; 
 wherein the EMI filter includes: 
 a plurality of signal electrodes arranged in an array, wherein each signal electrode extends from a top surface to a bottom surface of the filter such that the plurality of signal electrodes are flush with the top and bottom surfaces of the filter; 
 a plurality of ground electrodes arranged in parallel to each other and interposed between the plurality of signal electrodes, and arranged so as to be connected to at least one location on each of the top and bottom surfaces of the filter; and 
 dielectric material disposed between the plurality of signal electrodes and the plurality of ground electrodes to act as insulator material between adjacent signal and ground electrodes, and to define a filter body having a length along a longitudinal axis thereof, a thickness between the top and bottom surfaces thereof, and a width in the axis perpendicular to the longitudinal axis and the thickness; and 
 the upper termination area comprises respective termination surfaces coupled with the plurality of signal electrodes and coupled with the plurality of ground electrodes, and the bottom termination area comprises respective termination surfaces coupled with the plurality of signal electrodes and coupled with the plurality of ground electrodes, so that the filter acts as a shielding element to prevent unwanted electromagnetic interference with an input and output of the implanted medical device; 
 each of said plurality of signal electrodes have a length dimension along the longitudinal axis of the filter which is less than one-half of the length of the filter along the longitudinal axis thereof; and 
 each of said plurality of ground electrodes have a length dimension along the longitudinal axis of the filter which is more than one-half of the length of the filter along the longitudinal axis thereof. 
 
     
     
       31. An EMI filter system as in  claim 30 , wherein the respective termination surfaces comprise metallization applied to selected regions of the top and bottom surfaces of the filter. 
     
     
       32. An EMI filter system as in  claim 30 , further including bonding material securing the external connections wires in the bushing.